In the field of light-sensitive color photographic materials, various attempts have been hitherto made to improve color reproducibility. They are, for example, (a) in the case of light-sensitive color negative materials, to impart a development restraining effect to layer interfaces, and (b) to impart an automask function attributable to colored couplers.
However, the techniques of the above (a) and (b) can not be said to have been accomplished in the sense of the color reproduction with fidelity. For example, yellow inclines to orange, green loses its chroma, and both of them turn dark. Also, yellowish green inclines to yellow, and magenta turns into a color slightly inclining to red. In particular, when it is attempted to reproduce yellowish green, lawns, for example, that must be yellow-green look withered to make visually bad impression, and this has offered an important problem. Such a problem is considered to greatly depend on the spectral sensitivity of light-sensitive materials.
Light-sensitive color photographic materials, for example, light-sensitive color negative materials, are spectrally sensitized for a red-sensitive layer, a green-sensitive layer and a blue-sensitive layer so as to respond to red light, green light and blue light, respectively. These three kinds of light-sensitive layers have an overlap each other in the spectral sensitivities.
Ideally speaking, the spectral sensitivities of the three kinds of light-sensitive layers may be bounded by specific wavelengths without gaps and also without overlaps to entirely fill up the visible region, but this kind of things is actually impossible.
The overlaps of spectral sensitivities bring about turbidity of colors to cause obstruction of the color reproducibility with fidelity in printing.
Also, if the spectral sensitivities are made sharp so as not to be overlapped, holes of sensitivities, so to speak, in other words, unsensitized portions, are produced in the boundary wavelength region to cause there absence of color information, also resulting in obstruction of color reproducibility with fidelity in printing.
For the reasons like this, the spectral sensitivities in actual light-sensitive color photographic materials are set in realizable limitations with appropriate sharpness and appropriate overlaps.